Cushioning dunnage is used as a protective packaging material when shipping an item in a container. The dunnage fills any voids and/or cushions the item in the container during shipping. Typical materials for forming cushioning dunnage include paper and plastic. Relatively complicated machines and methods are known for producing cushioning dunnage comprising resilient pillow-like strips from rolls of stock material. One such known machine is disclosed in U.S. Pat. No. 5,785,639. The known machines are disadvantageous in that they are suitable primarily for larger-scale productions and they are relatively expensive. There has long been a need in the packaging industry for a small and inexpensive device that creates and dispenses paper or other material for use as void fill and cushioning when shipping products in boxes or other containers. The apparatus and system disclosed in Applicant's above-identified related applications addressed this need.
The systems disclosed in the aforementioned related applications include a conversion assembly comprising a convex material shaping roller over which sheet stock material is drawn, and two pairs of spaced, parallel input rollers following the shaping roller through which the stock material is pulled by feed rollers to convert the sheet stock material into a three-dimensional cushioning product. In one disclosed embodiment the conversion involves reducing the width of the material so that random convolutions are formed in the material across the width of the material without folding back the edges of the material. It has been found that the convex material shaping roller of the previously disclosed conversion assembly introduces friction to the traveling stock material. This friction is caused by the convex shaping roller being rotated by the passing stock material contacting the larger diameter center portion of the roller. The smaller diameter lateral end surfaces of the roller then move more slowly than the traveling stock material to cause friction when sliding contact is made between these end surfaces and the stock material.
Applicant has attempted to reduce this friction by using a conversion assembly having a segmented convex roller assembly formed of a plurality of coaxial, independently rotatable rollers 9A, 9B and 9C as shown in FIG. 17, in place of a single convex shaping roller. Friction at the outer edges of the material is minimized with this arrangement because each material shaping roller of the convex roller assembly is free to rotate at a different speed than the adjacent roller as the rollers are engaged by the traveling stock material. However, there remains a need for a material shaping structure for a conversion assembly in a cushioning conversion system which provides more precise and consistent control of alignment of the longitudinal center line of the sheet stock material with the material shaping structure during conversion as the material travels through the conversion assembly of the system.